Display screen or portion thereof with an animated graphical user interface



FIG. 1 is a front view of a display screen or portion thereof with an animated graphical user interface showing a first image of the claimed design.

FIG. 2 is a second image thereof; and,

FIG. 3 is a third image thereof.

The outermost broken-line border shown in FIGS. 1-3 illustrates the perimeter of a display screen or a portion thereof, as well as the boundary of the claimed design, and forms no part of the claimed design. The remaining broken lines illustrate portions of a graphical user interface and form no part of the claimed design. The appearance of the animated images sequentially transitions between the images shown in FIGS. 1-3. The process or period in which one image transitions to another forms no part of the claimed design. 

CLAIM We claim the ornamental design for a display screen or portion thereof with an animated graphical user interface, as shown and described. 